Transformer.



No. 783,532. PATENTED FEB. 28, 1905.

I W. S. MOODY.

TRANSFORMER.

APPLICATION FILED JULY 21. 1904.

v? ru m flWE C T1 0 A; mw$ N M E 5 3. V 4 W W m 9 f \l I m r. I a I; H v "f? a E 5 V 5 E N W N UNITED STATES Patented February 28, 1905.

PATENT OEEIcE.

WVALTER S. MOODY, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NElV YORK.

TRANSFORMER.

SPECIFICATION forming part of Letters Patent No. 783,532, dated February 28, 1905.

Application filed July 21, 1904. Serial No. 217,441.

To all whmn it may concern;

Be it known that I, WALTER S. MooDY, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Transformers, of which the following is a specification.

This invention comprises means for drying the coils and cases of electrical apparatus, and is particularly applicable to high-voltage oilcooled transformers.

ln practice it has been found that the presence of a very small percentage of water in the oil-cooling bath of a transformer will decrease the insulating power of the oil to a marked degree, and as it is impossible to prevent the accummulation of moisture on the coils and case during shipping great care must be taken to thoroughly dry these parts before the oil is introduced into the case. Attempts have been made to dry the apparatus by short-circuit-ing the secondary coil and supplying sufficient current to the primary to bring the coils up to the maximum safe temperature. It is found, however, that this method does not insure a perfectly dry case, as parts of the case, particularly the lower part or base, are not adequately heated by the coils. To overcome these difficulties and others to be subsequently enumerated, the apparatus hereinafer described was devised.

It consists, essentially, of a heater arranged in the casing of the transformer and capable of heating the parts to a temperature sufficient to drive off the accumulated moisture.

In the drawings, Figure l is a side elevation of the transformer,partly in section,showing one form of heater. Fig. 2 is a plan view in section, taken on the line 2 2 of Fig. 1, with the transformer-coils removed. Fig. 3 shows a transformer in which the steam-compartment is cast integral with the base, and Fig. 4: shows a transformer equipped with an electrical heater.

In Fig. 1, 1 is the transformer-case, of ordinary construction; 2, the transformer-base; 3, the transformer-windings, and i a coil of pipe arranged in the base 2 and adapted to receive a hot fluid, preferably steam. By the use of steam as a circulating medium for the coil, a constant and predetermined temperature may be readily obtained and a thorough drying of the case and adjacent parts insured without danger of subjecting the insulation of the windings to a destructive heat. The steam-circulating coil may be cast integral with the base or attached in any convenient manner.

Instead of a coiled pipe the steam-compartment may be provided by casting a suitable chamber in the transformer-case, as shown in Fig. 3, in which 5 is the steam heating-chamber, having the inlet 6 and outlet 7 The lower wall of the steam-chamber slopes downward in the center toward the outlet to facilitate the escape of the condensed steam. While the drawings show the heaters attached to the base, it is evident that they would be equally effective if attached to the sides of the casing, particularly at the lower part of the same.

In the modification shown in Fig. 4, 8 is an electric heater insulated from the base by suitable insulating material 9 and adapted to receive current through the binding-posts 1O 11. It is obvious that either direct or alternating current may be used to heat the resistance 8. 1

Steam for use in the heating-coil shown in Fig. 1 will usually be available from the central-station equipment; but in cases where it is not the steam may be generated in a portable boiler provided with an electric heater. This boiler-heater could be advantageously connected in series with the short-circuited secondary during the heating of the windings.

While it is intended that the steam heatingcoil of Fig. 1 may be used in combination with electrical heating of the transformerwindings, it is obvious that the additional electrical heating is not essential.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. In afluid-cooled electrical apparatus, the combination of a case therefor, and a heater arranged in proximity to the case to dry the same.

2. In a fluid-cooled electrical apparatus, the

combination of a case therefor, and a heatingcompartment in operative relation thereto to heat the same.

3. In a fluid-cooled electrical apparatus, the combination of a case therefor, and a heatingcoil Within the lower portion of the case to heat the same.

4:. The combination of a transformer-ease and a fluid-carrying heating-coil adjacent to thereto to heat the same.

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